1. Field of the Invention
Embodiments of the invention relate to a coated seed. Further embodiments of the invention relate to a process for producing a coated seed. More specifically, embodiments of the invention relate to a coated seed obtained by coating a seed with a fungicide and at least one of an alkali metal formononetinate and form ononetin. Further embodiments may relate to providing a coated seed that has been genetically engineered to produce a protein having fungicidal activity and/or a vesicular arbuscular mycorrhizal (VAM) fungus enhancing composition and/or any other protein conferring any trait whatsoever. Coatings of the invention stimulate plant growth and yields from the coated seeds by stimulating growth of beneficial mycorrhizal fungi and depressing growth of other pathogenic fungi on roots. “MYCONATE®” is the commercial or trade name for preparations of formononetin and/or potassium formononetinate. In the following, when the term MYCONATE® is used care has been taken to designate whether formononetin or potassium formononetinate was used in the preparation in question. MYCONATE® is a registered trademark of VAMTech, LLC.
2. Background
Mycorrhiza is a symbiotic mutualistic relationship between special soil fungi and fine plant roots; it is neither the fungus nor the root, but rather the structure formed from these two partners (Muchovej, R. M. “Importance of Mycorrhizae for Agricultural Crops” Florida Cooperative Extension Service Bulletin SS-AGR-170 (2001)). Vesicular arbuscular mycorrhiza is a type of mycorrhiza in which the fungus penetrates the cortical cells of the roots of a vascular plant. Vesicular arbuscular mycorrhizae are characterized by the formation of unique structures such as arbuscles and vesicles by fungi of the phylum Glomeromycota. These fungi help plants capture water and nutrients such as phosphorus and micronutrients from the soil. This symbiosis is a highly evolved mutualistic relationship between fungi and plants, the most prevalent plant symbiosis known (Simon, L. et al. “Origin and diversification of endomycorrhizal fungi and coincidence with vascular land plants” Nature 363:67-69 (1993)).
Vesicular arbuscular mycofrhizae are known to occur in approximately 80% of vascular plant families, including agriculturally important crops (Schussler, A. et al., “A new fungal phylum, the Glomeromycota: phylogeny and evolution” Mycological Research 105(12):1416 (2001)). Over the past 40 years, advances in mycorrhizal fungal physiology and ecology have led to applications of VAM fungi to improve ecosystems and production agriculture. One such application to increase the contribution of this symbiosis in annual crops is to maximize the activity of indigenous fungi through use of flavonoids to stimulate vesicular arbuscular mycorrhizal growth (Siqueira, J. O. et al., “VA-mycorrhizae and mycorrhiza stimulating isoflavonoid compounds reduce herbicide injury” Plant and Soil 134:233-242 (1991); Siqueira, J. O. et al., “Stimulation of vesicular-arbuscular mycorrhiza formation and growth of white clover by flavonoid compounds” New Phytologist 118:87-93 (1991)).
Flavonoids constitute a broad class of secondary metabolites produced by plants and are commonly found in roots, seeds and various plant organs (Graham, T. L. “Flavonoid and isoflavonoid distribution in developing soybean seedling tissues and in seed and root exudates” Plant Physiology 95(2):594-603 (1991)). One such flavonoid isolated from clover roots grown under phosphate stress conditions was identified and characterized as formononetin (4′-methoxy, 7-hydroxy isoflavone) (Nair, M. G. et al., “Isolation and identification of vesicular-arbuscular mycorrhiza-stimulatory compounds form clover (Trifolium repens) roots” Applied and Environmental Microbiology 52(2):434-439 (1991)). Various studies have demonstrated formononetin stimulates root colonization and/or hyphal formation and growth of vesicular arbuscular mycorrhizae when applied to plants at concentrations of 4-5 mg/L (Nair, M. G. et al. “Isolation and identification of vesicular-arbuscular mycorrhiza-stimulatory compounds form clover (Trifolium repens) roots” Applied and Environmental Microbiology 52(2):434-439 (1991); Siqueira, J. O. et al. “VA-mycorrhizae and mycorrhiza stimulating isoflavonoid compounds reduce herbicide injury” Plant and Soil 134:233-242 (1991); Siqueira, J. O., “Stimulation of vesicular-arbuscular mycorrhiza formation and growth of white clover by flavonoid compounds” New Phytologist 118:87-93 (1991); Baptista, M. J. & J. O. Siqueira “Effect of flavonoids on spore germination and a symbiotic growth of the arbuscular mycorrhizal fungus Gigaspora gigantea” Brazilian Journal of Plant Physiology 6(2):127-134 (1994); Koide, R. T, et al. “Strategies for mycorrhizal inoculation of six annual bedding plant species” HortScience 34(7):1217-1220 (1999); Davies, F. T. et al., “Influence of a flavonoid (formononetin) on mycorrhizal activity and potato crop productivity in the highlands of Peru” Scientia Horticulturae 106:318-329 (2005); Fries, L. L. M. “Influence of phosphorus and formononetin on isozyme expression in the Zea mays-Glomus intraradices symbiosis” Physiologia Plantarum 103:172-180 (1998); Ozan, A., et al. “Isozyme activity of developing Trifolium-Glomus mycorrhiza and associated effects of the isoflavone formononetin” Allelopathy Journal 3(2):217-228 (1996); Da Silva, J. P. & Siqueira, J. O. “Soil-applied synthetic formononetin stimulates arbuscular mycorrhizal formation in corn and soybean” Brazilian Journal of Plant Physiology 9(1):35-41 (1997); Da Silva, J. P. & Siqueira, J. O. “Mycorrhizal colonization and growth of soybean influenced by different fungal species and application of the isoflavonoid formononetin” Pesquisa Agropecuaria Brasileira 33(6):953-959 (1998). Additionally, various studies with formononetin have found significant increases in plant growth and biomass (Siqueira, J. O., et al. “Stimulation of vesicular-arbuscular mycorrhiza formation and growth of white clover by flavonoid compounds” New Phytologist 118:87-93 (1991); Davies, F. T. “Influence of arbuscular mycorrhizae indigenous to Peru and a flavonoid on growth, yield, and leaf elemental concentration of ‘Yungay’ potatoes” HortScience 40(2):381-385) (2005); and reduced plant disease (Elmer, W. “Influence of formononetin and NaCl on mycorrhizal colonization and Fusarium crown and root rot of asparagus” Plant Disease 86(12):1318-1324 (2002)). The chemical name for formononetin is 4′-methoxy, 7-hydroxy isoflavone (CAS# 485-72-3).
U.S. Pat. Nos. 5,002,603; 5,085,682; and 5,125,955 report the use of formononetin, an isoflavonoid, as a stimulant for the growth of vesicular arbuscular mycorrhizal fungi (“VAM fungi”) on roots of plants forming the beneficial mycorrhizal association. U.S. Pat. No. 5,691,275 reports the use of alkali metal formononetinate as a stimulant for the growth of VAM fungi. VAM fungi allow improved plant growth for many plant species by increasing nutrient and water uptake, synthesis of growth-promoting substances, drought tolerance, salinity and transplant shock tolerance, and interaction with other beneficial microorganisms. (Turk, M. A., et al., “Significance of Mycorrhizae” World J. of Agricultural Sci. 2(1): 16-20 (2006)).
A number of fungicides are available for agricultural and horticultural use. These include, for example, those listed in Table 1, which was obtained in part from Sweets, L., “Soybean Seed Treatment Fungicides,” Integrated Pest & Crop Management Newsletter (Univ. of Missouri-Columbia) 16(1) (Jan. 20, 2006) and in part from University of Missouri Extension, “Disease Management—Corn” 2005 Missouri Pest Management Guide: Corn, Soybean, Winter Wheat; and University of Missouri Extension, M171: 2007 Missouri Pest Management Guide: Corn, Grain Sorghum, Soybean, Winter Wheat and in part from personal knowledge and experience of the inventors. Although these articles focus on soybean, corn and winter wheat fungicides, those fungicides may have uses as seed treatments in many other seed crops as well.
TABLE 1Examples of Product Trade NamesActive Ingredient(Company)metalaxylAllegiance Dry (Trace Chemicals LLC)Allegiance-FL (Gustafson LLC)Allegiance-LS (Gustafson LLC)mefenoxamApron XL LS (Syngenta)azoxystrobinProtege FL (Gustafson LLC)Dynasty (Syngenta)captanBean Guard (Trace Chemicals LLC.)Captan 30-DD (Gustafson LLC)Captan 400 (Gustafson LLC)Captan 400 C (Gustafson LLC)Enhance (Trace Chemicals LLC)HiMoly/Captan-D (Trace Chemicals LLC)Rival Flowable (Gustafson LLC)Vitavax M DC (Helena)carboxinBean Guard (Trace Chemicals LLC)Enhance (Trace Chemicals LLC)Kernel Guard Supreme (Trace Chemicals LLC)RTU-Vitavax-Thiram (Gustafson LLC)Vitaflo-280 (Gustafson LLC)Vitavax CT (Helena)Vitavax M DC (Helena)Vitavax M (Helena)Vitavax-PCNB (Gustafson LLC)Vitavax T-L (Trace Chemicals LLC)Vitavax-200 (Gustafson LLC)Vitavax-34 (Gustafson LLC)fludioxonilMaxim 4FS (Syngenta)mancozebDithane DF Rainshield (Dow AgroSciences)Dithane F-45 Rainshield (Dow AgroSciences)Dithane M45 (Dow AgroSciences)Manzate 75 DF (Griffin LLC)Manzate 80 WP (Griffin LLC)Manzate Flowable (Griffin LLC)Penncozeb 75 DF (Cerexagri)Penncozeb 80 WP (Cerexagri)manebManex (Griffin LLC)PCNBRival Flowable (Gustafson LLC)RTU-PCNB (Gustafson LLC)Vitavax-PCNB (Gustafson LLC)TBZ (thiabendazole)LSP (Gustafson LLC)Rival Flowable (Gustafson LLC)RTU Flowable (Gustafson LLC)thiramProtector-D (Trace Chemicals LLC)Protector-L (Trace Chemicals LLC)RTU Flowable (Gustafson LLC)RTU-Vitavax-Thiram (Gustafson LLC)Triple Noctin L (Trace Chemicals LLC)42-S Thiram (Gustafson LLC)Vitaflo-280 (Gustafson LLC)Vitavax CT (Helena)Vitavax M (Helena)Vitavax T-L (Trace Chemicals LLC)Vitavax-200 (Gustafson LLC)trifloxystrobinTrilex (Gustafson LLC)fosetyl A1Aliette Super (Bayer CropScience)difenoconazoleDividend (Syngenta)tebuconazoleRaxil T (Bayer CropScience)Bacillus subtilisKodiak Concentrate Biological Fungicide(Gustafson LLC)Kodiak Flowable Biological Fungicide(Gustafson LLC)Kodiak HB (Trace Chemicals LLC)triadimenolBaytan 30 (Gustafson LLC)difenoconazole + mefenoxamazoxystrobin + metalaxylSoyGard (Gustafson LLC)captan + carboxin + metalaxylBean Guard Allegiance (Trace Chemicals LLC)captan + diazinonCaptan-Diazinon Seed Treater (Trace ChemicalsLLC)captan + lindaneSorghum Guard (Trace Chemicals LLC)captan + diazinon + lindaneKernel Guard (Trace Chemicals LLC)captan + diazinon + lindane + metalaxylAgrox Premiere (Agriliance LLC)captan + PCNB + thiabendazole + metalaxylRival Pak (Gustafson LLC)carboxin + maneb + lindaneEnhance Plus (Trace Chemicals LLC)carboxin + diazinon + lindaneGermate Plus (Trace Chemicals LLC)Kickstart (Helena Chemical Corporation)carboxin + metalaxyl + imidaclopridLatitude (Gustafson LLC)carboxin + PCNB + metalaxylPrevail (Trace Chemicals LLC)carboxin + permethrinKernel Guard Supreme (Trace ChemicalsLLC)carboxin + thiramVitaflo-280 (Gustafson LLC)carboxin + thiram + metalaxylStiletto (Trace Chemicals LLC)Stiletto Pak (Trace Chemicals LLC)chloroneb + mefenoxamCatapult XL (Agriliance, LLC)Delta Coat XL (Agriliance, LLC)chloroneb + metalaxylCatapult (Agriliance, LLC)Delta-Coat AD (Agriliance)mancozeb + lindaneGrain Guard Plus (Trace Chemicals LLC)mefenoxam + fludioxonilApronMAXX RFC (Syngenta)ApronMAXX RTA (Syngenta)ApronMAXX RTA + moly (Syngenta)Maxim XL (Syngenta)Warden RTA (Agriliance)metalaxyl + imidaclopridConcur (Agriliance LLC)thiram + metalaxylProtector-L-Allegiance(Trace Chemicals LLC)
Application of fungicides to plants may stimulate growth of plants by depressing growth of undesirable and/or pathogenic fungi, such as smuts, molds, rusts, and mildews. For example, a fungicide may be applied to suppress potato blight, wheat rust, wheat blight, wheat smut, or grape mildew.
One way that fungicide may be applied is as a seed treatment. This may be effective, for example, to suppress damage caused by seed decay, seedling blights, and root rots of certain seeds. Fungi that may cause this damage include, for example, species of the following genera: Pythium, Phytophthora, Rhizoctonia, Fusarium, Verticillium and Macrophomina. 
A fungicidal effect may also be achieved by providing a seed that has been genetically engineered to produce a protein that is able to reduce the growth of undesirable and/or pathogenic fungi. Such genetically engineered organisms are reported, for example, in Herrera-Estrella, L. & Simpson, J., “Genetically Engineered Resistance to Bacterial and Fungal Pathogens” World J. of Micro. & Biotech. 11(4): 383-392 (2004) and in U.S. Pat. No. 7,098,378, to Sainz, et al. Both of the foregoing are incorporated by reference herein.
Rarely, fungicides that may be applied to reduce, suppress or eliminate deleterious fungi may also have an adverse effect on growth of beneficial VAM fungi. For example, application of the fungicide pentachloronitrobenzene (PCNB) has been reported to decreased VAM-infected root length of oats (Avena sativa), thereby decreasing phosphorus uptake. (Gnekow, M. A. & Marschner, H., “Influence of the Fungicide Pentachloronitrobenzene on VA-mycorrhizal and Total Root Length and Phosphorus Uptake of Oats” Plant & Soil 114: 91-98 (1989)). Application of the fungicide chlorothalonil has been reported to decrease mycorrhizal colonization, phosphorus concentration, and dry matter yields of Leucaena leucocephala. (Azis, T., et al. “Inhibition of Mycorrhizal Symbiosis in Leucaena leucocephala by chlorothalonil” Plant & Soil 131(1): 47-52 (1991)).
Growth of the vesicular arbuscular mycorrhizal fungus Glomus mosseae has been reported to be affected by application of the fungicide benomyl. (Chiocchio, V., et al. “Effect of the Fungicide Benomyl on Spore Germination and Hyphal Length of the Arbuscular Mycorrhizal Fungus Glomus mosseae” Int'l Microbiol. 3:173-75 (2000)). VAM colonization of onion roots has also been reported to be depressed by application of fungicide. (Kough, J. L., et al. “Vesicular-arbuscular Mycorrhizal Fungi after Fungicide Applications” New Phytol. 106: 707-715 (1987)).